Anatomy Flashcards
HINDBRAIN
The hindbrain comprises:
-The myelencephalon (medulla oblongata and lower part of the fourth ventricle)
–The metencephalon (pons, cerebellum and intermediate part of fourth ventricle), and
-Isthmus rhombencephalon.
The medulla oblongata opens into the fourth ventricle.
The nucleus ambiguous gives rise to fibres of the accessory, vagus and glossopharyngeal nerves.
The locus caeruleus receives sensory fibres from the trigeminal nerve.
The three parts of the cerebellum include the vermis and the two hemispheres which are confluent.
The pyramids (spinothalamic tracts) are medial to the olives.
The median portion of the cerebellum is the vermis and the cerebellar hemispheres lie lateral to it.
Brachial Plexus
-Anterior rami of C5 to T1.
-Roots are located in the posterior triangle.
-Pass between the scalenus anterior and medius.
BRAIN TUMOURS METS
Tumours that most commonly spread to the brain include:
lung (most common)
breast
bowel
skin (namely melanoma)
kidney
Glioblastoma multiforme
Glioblastoma is the most common primary tumour in adults and is associated with a poor prognosis (~ 1yr).
Histology: Pleomorphic tumour cells border necrotic areas.
Meningioma
The second most common primary brain tumour in adults.
They arise from the arachnoid cap cells of the meninges.
Histology : Spindle cells in concentric whorls and calcified psammoma bodies.
Vestibular schwannoma
Benign tumour arising from the eighth cranial nerve (vestibulocochlear nerve). Often seen in the cerebellopontine angle.
Neurofibromatosis type 2 is associated with bilateral vestibular schwannomas.
- Histology: Antoni A or B patterns are seen. Verocay bodies (acellular areas surrounded by nuclear palisades
Pilocytic Astrocytoma
The most common primary brain tumour in children
* Histology: Rosenthal fibres (corkscrew eosinophilic bundle)
Medulloblastoma
A medulloblastoma is an aggressive paediatric brain tumour.
Histology: Small, blue cells. Rosette pattern of cells with many mitotic figures.
Ependymoma
Commonly seen in the 4th ventricle
* May cause hydrocephalus
* Histology: perivascular pseudorosettes
Oligodendroma
Benign, slow-growing tumour common in the frontal lobes
* Histology: Calcifications with ‘fried-egg’ appearance.
Haemangioblastoma
Vascular tumour of the cerebellum
* Associated with von Hippel-Lindau syndrome
* Histology: foam cells and high vascularity
Pituitary Adenoma
Pituitary adenomas are benign tumours of the pituitary gland. They are either secretory (producing a hormone in excess) or non-secretory. They may be divided into microadenomas (smaller than 1cm) or macroadenoma (larger than 1cm).
Craniopharyngioma
Most common paediatric supratentorial tumour
- A craniopharyngioma is a solid/cystic tumour of the sellar region that is derived from the remnants of Rathke’s pouch. It is common in children, but can present in adults also. It may present with hormonal disturbance, symptoms of hydrocephalus or bitemporal hemianopia.
Cardiac action potential
Phase 0 Rapid depolarisation Rapid sodium influx
These channels automatically deactivate after a few ms
Phase 1 Early repolarisation Efflux of potassium
Phase 2 Plateau Slow influx of calcium
Phase 3 Final repolarisation Efflux of potassium
Phase 4 Restoration of ionic concentrations Resting potential is restored by Na+/K+ ATPase
Cardiac physiology
> > Left ventricular ejection fraction = (stroke volume / end-diastolic LV volume ) * 100%
Cardiac output = stroke volume x heart rate
Pulse pressure = Systolic Pressure - Diastolic Pressure
Systemic vascular resistance = mean arterial pressure / cardiac output
Cerebral perfusion pressure
CPP= Mean arterial pressure - Intra cranial pressure
Skier’s thumb, Gamekeepers thumb
Damage to ulnar collateral ligament
